DESCRIPTION (Applicant's Description): The objectives of this proposal are to a) provide a structured, training program in molecular genetics for the applicant to develop into an independent researcher, and b) study the genetic events associated with overcoming senescence (i.e. immortalization) in human prostate epithelial cells. Numerous documentational studies have detailed patterns of genomic loss and gain in prostate cancers. However, the functional significance of many of these genetic events or combinations of genetic events remains unclear. Overcoming senescence can be considered a critical event in tumorigenesis that has a clear genetic basis. In the proposed model, human prostate epithelial cultures (HPECs) expressing viral oncoproteins lack normal pRB and/or p53 regulatory functions (genes commonly altered in clinical prostate cancers) and have an extended lifespan. These in vitro events place these cells at high risk for additional 'spontaneous' genetic and epigenetic alterations associated with immortalization. The applicants will test the hypothesis that combinations of these genetic events, complementing p53 and/or pRb loss, are important in overcoming cellular senescence in in vitro prostate cancer. In addition, they propose that these pathways are found in clinical prostate cancer specimens. Their SPECIFIC AIMS include: I) to establish and characterize an in vitro model system with immortal HPECs that have functionally lost p53 and/or Rb by selective HPV16 E6 and/or E7 retroviral infection, ii) to identify additional genetic and epigenetic events, chiefly combinations of events, associated with overcoming senescence for p53- and Rb-linked pathways, iii) to reexpress these genomic regions lost or gained at immortalization in immortal and normal HPECs, and iv) to correlate these in vitro events with clinical prostate cancer samples that have lost either p53 and/or Rb function. The proposal will provide new i n sight into molecular genetic and epigenetic events associated with overcoming senescence, via p53 and/or Rb loss of function, in prostate epithelial cells in vitro. In addition to addressing this critical mechanistic role in human prostate neoplasia, it will provide the applicant with a structured training program in molecular genetics in the laboratory of Dr. Catherine Reznikoff.